Just received a copy of CHETAH 8.0. This is a program for thermochemical and energy release evaluation and is distributed by ASTM. It will calculate enthalpy of combustion and thermochemical properties of compounds and reactions including- LFL, LOC, MIE, lower limit flame temperatures, maximum flame temperature, fundamental burning velocity, and quenching distance.
I have only had it installed for 2 days, so it’s way too early to give an appraisal. It came highly recommended by several colleagues in the process safety field. The only snag so far is a balky SMILES input module. This feature was very appealing because it allows one to copy a ChemDraw structure in SMILES format and paste it into the CHETAH GUI. The rep at ASTM gave me a link which ended up offering very cryptic instructions. Naturally, the problem is some obscure setting in Windows.
Until I get this fixed, I’ll have to enter Benson groups by hand. As it happens, I began studying guitar in my spare time, so there are all kinds of new things for my addled brain to stumble over assimilate. So when I’m not picking at strings, I’m picking at Benson groups.
Update 3/5/09: After a service pack download, the SMILES module is functioning. This is a very powerful tool.
We’ve recently caught up with the times and have been pressing Accelerating Rate Calorimetry (ARC) into service. Or more accurately, paying to have the data collected. ARC is really quite informative in that it can offer a Time to Maximum Rate (TMR) equation from which a TMR can be determined for any desired temperature. You can calculate an adiabatic delta T as well. I do not know how reliable this number is, but it certainly reminds one of the importance of considering the effect of phi factor in process scale up.
The ARC data I get includes an Antoine curve which can indicate that the accelerated rate behavior is or is not characteristic of classical liquid/vapour equilibrium behavior. What this says to the wary is that other volatiles (besides the subject material) may be generated which are not condensable. This is helpful in considering what kind of controllability is available to the process engineers.
Lamentations on Chemistry 
ARC runs are really fun, especially when you have a known decompostion process going. I particularaly like things that decarboxylate at 50 C (like glycidic acids….).
Good luck on the guitar, I have been at it for 20 years and still feel like there is an awful lot to learn. It has kept me sane for a long time.
One eagerly anticipates NASA parametric studies on the liquid fluorine/trimethylaluminum rocket engine. The liquid fluorine/diethylberyllium engine was sooo close! Ditto liquid ozone/B2H6 (ozone being a natural, sustainable oxidizer. Liquid fluorine is yellow and therefore obviously impure). “The prototype was CNC milled from a one tonne forged ingot of iridium…”
One can hardly wait to watch the cryogenic filling hoses being disconnected. Will there be models of that, too?
F2/Me3Al ???? Holy cats!
Click to access naca-rm-e9c11.pdf
They really were that… adventuresome.
KISS. Solid forged 6061-T6 aluminum cylinder with a hole drilled own the center. Add exhaust bell and a liquid fluorine turbopump – there’s your hybrid rocket engine. Might wrap the cylinder with carbon fiber-epoxy to cover butt.
F2/Me3Al – for when your relatives don’t have the money to afford a matchbox as a coffin.